$10lm + 6ln - 7l + 8 = 3m - 6$ Solve for $l$.
Solution: Combine constant terms on the right. $10lm + 6ln - 7l + {8} = 3m - {6}$ $10lm + 6ln - 7l = 3m - {14}$ Notice that all the terms on the left-hand side of the equation have $l$ in them. $10{l}m + 6{l}n - 7{l} = 3m - 14$ Factor out the $l$ ${l} \cdot \left( 10m + 6n - 7 \right) = 3m - 14$ Isolate the $l$ $l \cdot \left( {10m + 6n - 7} \right) = 3m - 14$ $l = \dfrac{ 3m - 14 }{ {10m + 6n - 7} }$